doc: Mention python dep in downloads page

Closes #3604
blog: v0.11.6
uv: Upgrade v0.10.14
2013.08.21, Version 0.10.17 (Stable)

* uv: Upgrade v0.10.14

* http_parser: Do not accept PUN/GEM methods as PUT/GET (Chris Dickinson)

* tls: fix assertion when ssl is destroyed at read (Fedor Indutny)

* stream: Throw on 'error' if listeners removed (isaacs)

* dgram: fix assertion on bad send() arguments (Ben Noordhuis)

* readline: pause stdin before turning off terminal raw mode (Daniel Chatfield)
Merge branch 'v0.10.17-release' into v0.10
Now working on 0.10.18
blog: Post for v0.10.17
tools: script to report [un]stable build
tools: script release steps after jenkins build
uv: update to v0.10.15
uv: upgrade to v0.11.10
process_wrap: don't coerce process exit code to int32_t

On windows process exit codes can be greater than INT32_MAX. This used
to be not much of a problem - greater values would just come out
negative. However since ca9eb71 a negative result value indicates that
uv_spawn() has failed, so this is no longer acceptable.
src: remove pointless node_os.h header file

src/node_os.cc doesn't export anything that's used elsewhere. Remove it.
buffer: add NativeBuffer API

Due to a lot of the util.is* checks there was much unnecessary overhead
for the most common use case of Buffer. Which is creating a new Buffer
instance for data from incoming I/O. NativeBuffer is a simple way to
bypass all the unneeded checks and simply hand back a Buffer instance
while setting the length.
buffer: fix assert fail from JS API

Length arguments passed to SlowBuffer were coerced to Int32, not Uint32,
so passing a negative number would throw the following:

node: ../src/smalloc.cc:244: void node::smalloc::Alloc(): Assertion `length <= kMaxLength' failed.
Aborted (core dumped)

That has been fixed by coercing to Uint32 and comparing the value
against kMaxLength.
src: fix up unused/unordered imports
cares_wrap: drop UV_HANDLE_FIELDS from ares_task_t

UV_HANDLE_FIELDS is a libuv implementation detail.  The ares_task_t
struct only uses the uv_loop_t* field so be explicit about that.
src: remove --max-stack-size option

Ad-hoc duplicate of V8's --stack-size option.  Superfluous in other
words.  Remove it.
src: call uv_loop_delete() on exit in debug mode

Should make tracing with valgrind a little easier on the eye and
possibly help expose libuv handle lifecycle issues.
src: remove two pointless globals from node.cc

De-globalize use_npn and use_sni, they're only used in GetFeatures().